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Is it possible to prevent any and all monitor spanning? I have zero use cases when I want a window to span across my 2 monitors but frequently I have windows opening partially on my 4k monitor and partially on my 1440p monitor which throws off the window size.
You could create a Trigger rule for all windows that maximizes the window when it opens. That way any time a window opens it maximizes to whatever monitor it's mostly on.
To make a Trigger rule apply to all applications, set the Process Filename to